History[edit]
It was founded in 712/11 BC as a
MegarianMegarian colony and was originally
known as Astacus (/ˈæstəkəs/; Ancient Greek: Ἀστακός,
"lobster").[2] After being destroyed by Lysimachus,[3] it was rebuilt
by
Nicomedes I of Bithynia in 264 BC under the name of Nicomedia, and
has ever since been one of the most important cities in northwestern
Asia Minor. The great military commander
HannibalHannibal Barca came to
NicomediaNicomedia in his final years and committed suicide in nearby Libyssa
(Diliskelesi, Gebze). The historian
ArrianArrian was born there.

This section of a belt depicting medallions honoring Constantius II
and Faustina was minted in Nicomedia.[4] The Walters Art Museum.

NicomediaNicomedia was the metropolis and capital of the Roman province of
BithyniaBithynia under the Roman Empire. It is referenced repeatedly in Pliny
the Younger's Epistles to Trajan during his tenure as governor of
Bithynia.[5]
DiocletianDiocletian made it the eastern capital city of the Roman
Empire in 286 when he introduced the
TetrarchyTetrarchy system.
Persecutions of 303[edit]
NicomediaNicomedia was at the center of
DiocletianDiocletian and his Caesar Galerius'
persecution of the Christians. On 23 February 303 AD, the pagan
festival of the Terminalia,
DiocletianDiocletian ordered that the newly-built
church at
NicomediaNicomedia be razed, its scriptures burnt, and its precious
stones seized.[6] The next day he issued his "First Edict Against the
Christians," which ordered similar measures to be taken at churches
across the Empire.
The destruction of the
NicomediaNicomedia church incited panic in the city, and
at the end of the month a fire destroyed part of Diocletian's palace,
followed 16 days later by another fire.[7] Although an investigation
was made into the cause of the fires, no party was officially charged,
but
GaleriusGalerius placed the blame on the Christians. He oversaw the
execution of two palace eunuchs, who he claimed conspired with the
Christians to start the fire, followed by six more executions through
the end of April 303. Soon after
GaleriusGalerius declared
NicomediaNicomedia to be
unsafe and ostentatiously departed the city for Rome, followed soon
after by Diocletian.[7]
Later Empire[edit]
NicomediaNicomedia remained as the eastern (and most senior) capital of the
Roman EmpireRoman Empire until co-emperor
LiciniusLicinius was defeated by Constantine the
Great at the
Battle of ChrysopolisBattle of Chrysopolis (Üsküdar) in 324. Constantine
mainly resided in
NicomediaNicomedia as his interim capital city for the next
six years, until in 330 he declared the nearby
ByzantiumByzantium (which was
renamed Constantinople) the new capital. Constantine died in a royal
villa in the vicinity of
NicomediaNicomedia in 337. Owing to its position at
the convergence of the Asiatic roads leading to the new capital,
NicomediaNicomedia retained its importance even after the foundation of
Constantinople.[8]
A major earthquake, however, on 24 August 358, caused extensive
devastation to Nicomedia, and was followed by a fire which completed
the catastrophe.
NicomediaNicomedia was rebuilt, but on a smaller scale.[9] In
the sixth century under Emperor
Justinian IJustinian I the city was extended with
new public buildings. Situated on the roads leading to the capital,
the city remained a major military center, playing an important role
in the Byzantine campaigns against the Caliphate.[10]
In 451, the local bishopric was promoted to a Metropolitan see under
the jurisdiction of the Ecumenical Patriarchate of Constantinople.[11]
The metropolis of
NicomediaNicomedia was ranked 7th in the Notitiae
Episcopatuum among the metropolises of the patriarchate.[12] In the
eighth century the Emperor
Constantine VConstantine V established his court there
for a time, when plague broke out in
ConstantinopleConstantinople and drove him from
his capital in 746–47.[13] From the 840s on,
NicomediaNicomedia was the
capital of the thema of the Optimatoi. By that time, most of the old,
seawards city had been abandoned and is described by the Persian
geographer Ibn Khurdadhbih as lying in ruins, with settlement
restricted to the hilltop citadel.[10] In the 1080s, the city served
as the main military base for
Alexios I KomnenosAlexios I Komnenos in his campaigns
against the Seljuk Turks, and the First and Second Crusades both
encamped there.
The city was briefly held by the
Latin EmpireLatin Empire following the fall of
ConstantinopleConstantinople to the
Fourth CrusadeFourth Crusade in 1204: in late 1206 the
seneschal Dietrich von Los made it his base, converting the church of
Saint Sophia into a fortress; however, the Crusader stronghold was
subjected to constant raids by the
Emperor of NicaeaEmperor of Nicaea Theodore I
Laskaris, during which von Los was captured by Nicaean soldiers; by
the summer of 1207 Emperor
Henry of FlandersHenry of Flanders agreed to evacuate
NicomediaNicomedia in exchange for von Los and other prisoners Emperor Theodore
held.[14] The city remained in Byzantine control for over a century
after that, but following the Byzantine defeat at the Battle of
Bapheus in 1302, it was threatened by the rising Ottoman beylik. The
city was twice blockaded by the Ottomans (in 1304 and 1330) before
finally succumbing in 1337.[10]
Infrastructure[edit]
During the Empire,
NicomediaNicomedia was a cosmopolitan and commercially
prosperous city which received all the amenities appropriate for a
major Roman city.
NicomediaNicomedia was well known for having a bountiful
water supply from two to three aqueducts,[15] one of which was built
in Hellenistic times.
Pliny the YoungerPliny the Younger complains in his epistulae to
Trajan that the Nicomedians wasted 3,518,000 sesterces on an
unfinished aqueduct which twice ran into engineering troubles. Trajan
instructs him to take steps to complete the aqueduct, and to
investigate possible official corruption behind the large waste of
money.[16] Under Trajan, there was also a large Roman garrison.[17]
Other public amenities included a theatre, a colonnaded street typical
of Hellenistic cities and a forum.[18]
The major religious shrine was a temple of Demeter, which stood in a
sacred precinct on a hill above the harbor.[5] The city adopted
official cults of Rome avidly, there were temples dedicated to the
Emperor Commodus,[19] a sacred precinct of the city dedicated to
Octavian,[20] and a temple of Roma dedicated during the
late-Republic.[5]
The city was sacked in AD 253 by the Goths, but when
DiocletianDiocletian made
the city his capital in 283 AD he undertook grand restorations and
built an enormous palace, an armory, mint and new shipyards.[5]
Notable natives and residents[edit]

Remains[edit]
The ruins of
NicomediaNicomedia are buried beneath the densely populated modern
city of Izmit, which has largely obstructed comprehensive excavation.
Before the urbanization of the 20th century occurred, select ruins of
the Roman-era city could be seen, most prominently sections of the
Roman defensive walls which surrounded the city and multiple aqueducts
which once supplied Nicomedia's water. Other monuments include the
foundations of a 2nd-century AD marble nymphaeum on
IstanbulIstanbul street, a
large cistern in the city's Jewish cemetery, and parts of the harbor
wall.[5]
The 1999
İzmitİzmit earthquake, which seriously damaged most of the city,
also led to major discoveries of ancient
NicomediaNicomedia during the
subsequent debris clearing. A wealth of ancient statuary was
uncovered, including statues of Hercules, Athena,
DiocletianDiocletian and
Constantine.[21]
In the years after the earthquake, the Izmit Provincial Cultural
Directorate appropriated small areas for excavation, including the
site identified as Diocletian's Palace and a nearby Roman theatre. In
April 2016 a more extensive excavation of the palace site was begun
under the supervision of the Kocaeli Museum.[22]
See also[edit]